I had this weird problem with power steering for quite some time now. As I would turn the wheel sometimes it would become really stiff to turn for no reason and other times it would turn really smooth. Also, I could barely turn the wheel while standing in idle. I thought it could be the steering box or the power steering pump but they look fine. I remember at one point the high pressure line blew up and sprayed fluid all over the engine bay. After replacing that, the power steering pump blew up and fluid was everywhere again. So I went with a reman one for that. I thought after all this the problem would go away but 2 years later it was still acting weird. So today I decided to do something about it. After speaking with a few experts it turned out that the steering shaft was lacking lube and after lubing up the shaft with some penetrating oil it was way better as I could now turn the wheel while standing still. Its still a little on the stiff side but maybe lubing it up some more will fix the problem. I'm thinking about buying a new shaft for it but don't know if that is worth doing.
Any input is appreciated...